Electrostatic chucks are used as means to adhere and hold an object to be processed (such as a semiconductor wafer or a glass substrate) in a plasma processing chamber that performs etching, chemical vapor deposition (CVD), sputtering, ion implantation, ashing, and the like.
Electrostatic chucks are fabricated by interposing an electrode between ceramic substrates of alumina or the like and sintering the arrangement. Electrostatic chucks apply an electrostatic adhesion-use power to the internal electrode and thereby adhere a substrate such as a silicon wafer or the like by an electrostatic force.
Recently, in an etching apparatus based on plasma, there is a trend of higher output of plasma. With the higher output of plasma, the heat amount supplied to the wafer is increased. In the case where the heat amount supplied to the plasma is relatively low, a temperature change of the electrostatic chuck is relatively small and a relatively small chiller is available. In the case where the heat amount supplied to the wafer is relatively low, use of a cooling metal plate which does not need a coolant and change of the chiller temperature are sufficiently available so that the wafer is set to a desired temperature in the processing.
However, as the heat amount supplied to the wafer is relatively increased and the temperature of the ceramic base material is increased, the temperature of the wafer is increased. Then, there is a problem that materials which can be used for the wafer processing are limited to high heat resistance material.
On the other hand, there is an electrostatic chuck having a built-in heater for uniformization of the temperature distribution in the plane of the wafer.
Uniformity of the temperature distribution in the plane of the wafer is desired.